The present invention relates to an improved fuze, for detonating the explosive charge of a projectile, of the type designed for initiation of the fuze by wide-angle or graze impact, sometimes called "All Way" fuzes. Most fuzes designed for direct or head-on impact with a target become less and less reliable as the angle of incidence increases, and become inoperative at grazing angles. Thus, it has become necessary to design fuzes especially for grazing impact, while retaining the ability to respond to direct impact.
Some all-way fuzes incorporating inertial weights have been proposed. For example, in G. Webb U.S. Pat. No. 3,371,608, the firing pin of the fuze is actuated by a spherical ball weight that shifts laterally on graze impact and engages a conical surface on the firing member to actuate the latter in opposition to a biasing spring. One disadvantage of this device is that the mass of the ball weight is small compared to the mass of the firing member.
An object of the present invention is to provide an improved inertial, all-way, impact fuze. In accordance with the invention, a firing member of relatively small mass is actuated by engagement of a circular flange thereon by an internal conical surface on one end of an annular inertial member of relatively large mass, which shifts laterally in the fuze housing on graze impact of the fuze with a target. The inertial member pivots about a fulcrum formed by engagement of the other end thereof with the housing wall.